Tumor formtion , ti ri plasmid , dna trnsfr.

Ti-Ri plasmid ,tumor formation and some DNA transfer methods are described here..

1. St. THOMAS COLLEGE RUABANDHA TOPIC : BASIS OF TUMOR FORMATION , Ti- Ri PLASMID & DNA TRANSFER. ( PAPER-7 - PLANT BIOTECHNOLOGY) GUIDED BY : SUBMITTED BY: Dr. UJJWALA SUPE V. SUKIRTI M.Sc. II SEMESTER BIOTECHNOLOGY YEAR:- 2016-17

2. SYNOPSIS INTRODUCTION. BASIS OF TUMOR FORMATION. AGROBACTERIUM. Ti- PLASMID. OPINES. HOW Ti- PLASMID CAUSE A DISEASE? T- DNA. Ri – PLASMID. HOW Ri – PLASMID CAUSE A DISEASE ? DNA TRANSFER. REFERENCES.

3. INTRODUCTION Agrobacterium is a pathogenic bacteria that causes tumor in plants . Ti- plasmid causes crown gall disease in plants. Small part of Ti- plasmid ( T- DNA ) is transferred into plant genome. Ri – plasmid cause hairy root diseases in plants. DNA transfer - The foreign DNA transformation of bacterial cells and its subsequent integration into the genetic material of host.

4. BASIS OF TUMOR FORMATION Agrobacterium tumefaciens causes tumor in plants i.e. crown gall disease. Agrobacterium rhizogenes causes hairy root disease. The tumor formation results from the transfer of particular set of Ti & Ri – plasmid into plant chromosome. Tumor formation occur by transfer of small segment of Ti – plasmid. (T- DNA).

5. AGROBACTERIUM T here are two main species of agrobacterium :- Agrobacterium tumefaciens - Infects damaged plant tissue which is induced plant tumor i.e. crown gall. Crown gall occurs when bacterium releases Ti – plasmid into cytoplasm. 2. Agrobacterium rhizogenes - induces hairy root disease. Bacterial genes transfer its T- DNA from its Ri - plasmid into plant through wound.

6. Ti- PLASMID Extra chromosomal , double stranded circular DNA molecule . Vir genes helps in transfer of T-DNA into plant cell. Small segment of Ti- plasmid transferred to host plant & integrated with genome i.e. T-DNA. Agrobacterium induced tumors synthesize variety of unusual compounds- opines.

7. OPINES Agrobacterium induce tumors synthesize a variety of unusual compounds called opines . T ypes of opines:- Octapine Nopaline Agropine These opines are catabolized by agrobacterium to obtain energy.

8. HOW Ti- PLASMID CAUSE A DISEASE?

9. T- DNA O nly a small segment of Ti- plasmid is transferred to the host plant cell & gets integrated with genome i.e. T – DNA . It contains genes for tumor formation ( Tum) & nopaline biosynthesis ( Nos ). T-DNA is bordered by 25 bp repeats , required for excision & transfer of DNA.

10. Ri- PLASMID The virulence plasmid of A.rhizogenes is commonly known as Ri- Plasmid (pRi) . Agrobacterium rhizogene is a soil borne , gram negative bacterium. It causes hairy root disease in plants . All strains of A.rhizogenes are known to produce agrocinopine.

11. HOW Ri –PLASMID CAUSE A DISEASE?

12. DNA TRANSFER The insertion of a DNA fragment (gene of interest) into a cloning vector & then its introduction into a suitable host. The uptake of isolated plasmid directly by plant protoplast can be done by following DNA gene transfer methods :- Electroporation. Microprojectile bombardment. Microinjection.

13. 1. ELECTROPORATION It involves the use of high field strength electric impulses . It results in the formation of transient pores in the plasma membrane through which DNA enters & gets integrated into the host cell genome. This technique is simple, convenient & rapid.

14. 2. MICROPROJECTILE BOMBARDMENT This method is used for delivery of foreign genes into plant cells or tissues . Exogenous DNA or RNA molecules can be coated to the surface of microscopic tungsten microprojectiles. These are then accelerated to high velocities by a particle gun, enabling them to pierce cell walls & membranes.

15. 3. MICROINJECTION. This technique involves animal cells transformation at high frequency . Protoplasts are surface attached on a slide by embedding in agarose or polylysine using a holding pipette. DNA is transferred by injecting it with microneedles into surface- attached protoplast. After this the recipient cell is kept in position by a suction holding pipette.

16. REFERENCES. K.G.RAMAWAT – PLANT BIOTECHNOLOGY (2004) . 3 rd EDITION, S.CHAND AND COMPANY Ltd. PAGE NO. 231-238, 183 . M.K. RAZDAN – INTRODUCTION TO PLANT TISSUE CULTURE (2012). 2 nd EDITION, OXFORD & IBH PUBLISHING Co. Pvt. Ltd. PAGE NO. – 186-189.

17. THANK YOU..